Having dived into the Chapter 4 Weird Route stuff, I actually am looking back at how Kris acts towards Tenna in chapter 3. I know the fandom take is that Kris hates Tenna, but I honestly honestly honestly don't think it's true, especially with Weird Route Kris in mind.
For all of Chapter 3, Kris is undoubtedly cold toward Tenna, but if we consider the idea that Kris is aware to some degree of what opening the fountains likely or possibly entails, they might have known that Tenna was possibly in for a poor fate. Also, Kris not only participates but gets INTO Tenna's games. Yes the soul chooses which pose Kris does in the band game, but we've learned that Kris can modulate the degree to which they do what the soul commands, and they still put their ass into that pose and seem to legitimately enjoy it.
I think being with Tenna is *conflicting* for Kris more than a drag. Tenna represents the times when things were good at home, after all, and all of his memories are around when the Dreemurr and Holiday families were close and happy, and without context for how things have changed, Kris has to face those memories as well. And Kris has been desperate to avoid anything to remind them of that time. They refuse to let the Soul see really anything about Asriel, they try to avoid reading anything about Asgore.
I think Kris loves Tenna in a thoroughly melancholic way. There is grief in Kris' love for Tenna, especially in the wake of the Soul. Tenna and Noelle are the only ones who noticed and recognize that there is something off about Kris, granted Tenna notices it when he's crashing out. Tenna and Noelle are the only tethers to that happier time, and I think to that end it's noteworthy that Kris wakes up in Chapter 4 next to the television, as if holding vigil (either because he was recovering or because he's truly gone depending on how Ch3 is handled).
I feel like we'll need the rest of the game to truly know the motive for Kris opening the dark world in their house. Going into Chapter 3 I thought it was because Kris was legitimately enjoying and loving spending time in the dark worlds with their friends, and Queen had told the lot of them how to make one, so they did it themselves to be able to continue to be connected to the people they love, which is also why Tenna was turned on. Kris wanted to spend time with Tenna, having learned at the start of Chapter 2 how the Light World items translated to Darkners.
Chapter 4 throws a little bit of a wrench into that assumption, but not enough that I am dismissing it entirely. Even if the prophecy demands certain things happen, we're learning it can be redefined. If Kris doesn't know about the prophecy, or isn't being told about the prophecy, they may have just been told that there needed to be a Dark World opened and happily chose to see Tenna to make it happen.
So many thoughts, that's all I'll say for now though.
